of ordinary Portland cement. Water-cement ratio was 0.40 and cement-sand ratio was 1:3. The content of nano-TiO2 was 3% but the content of nano-SiO2 changed in cement mortars. The content of nano-SiO2 was 0%, 0.5%, 1%, 1.5% and 2% of the binder weight. Mortar prisms and beams were made in specified molds and cured in limewater. Compressive and flexural strengths, porosity and ultrasonic pulse velocity were measured. Then mortars were stored in 6 molar ammonium nitrate (NH4NO3) solution. Leaching depth, variation of mechanical and microstructural properties were measured. Presence of nano-particles decreased the leaching depth and the degradation of mechanical and microstructural properties in mortars.

• 아따 아르 헤르만(한양대학교, 콘크리트연구실) | Atta-ur-Rehman
• 압둘쿠두스(한양대학교, 콘크리트연구실) | Abdul Qudoos
• 김준형(한양대학교, 콘크리트연구실) | Kim Jun Hyeong
• 김홍기(한양대학교, 콘크리트연구실) | Kim Hong Gi
• 류재석(한양대학교) | Ryou Jae Suk